It turns out that Twitter is easier to use than Google (via OpenID). One of my issues is that google returns different authentications depending on the requesting URL. This really sucks if your web-app is accessable by different URL’s (e.g. in development) etc. so you need to maintain another authorization for each of them.

However now it’s there and ready to use. Additionally I used the new Rails 3 mailer API to add some confirmation step for the Email Address of new Users.